Conventionally, biphenyl derivatives have been prepared by a coupling reaction under various reacting condition.
Ann. (1904), 332, 38 and JP4-257564 discloses Ullman coupling reaction of halobenzene derivatives in the presence of metal, Na or Cu etc.
Bull. Chem. Soc. Jpn. (1976), 49, 1958 teaches a nickel-phosphine complex catalyzed coupling of aryl Grignard reagent with haloaryl derivative.
JP6-9536 discloses a cross coupling reaction of 2-chlorobenzonitrile and aryl Grignard reagent in the presence of MnCl.sub.2.
Synth. Commun. (1981), 11, 513 teaches palladium catalyzed coupling reaction of aryl iodide, aryl bromide or aryl trifulate with aryl boronic acid derivative.
A major disadvantage of coupling processes in the art is 1) use of expensive starting material and catalyst, 2) low selectivity of the reaction resulted in a mixture of homo and cross coupling products, 3) difficulty in isolation and purification processes, 4) handling of highly reactive reagents, Grignard reagent etc.
Construction of benzene ring is another method to prepare biphenyl derivatives. JP9-87238 discloses a cycloaddition reaction of .alpha.-cyanocinnamate derivative with butadiene to afford benzene substituted cyclohexene derivative followed by aromatization. This method needs high pressure and temperature in the cycloaddition process.
The present invention provides an industrial process by which biphenyl derivatives can be prepared in a high selectivity and yield and which is free from the above-mentioned disadvantages.